Squash is a warm-season crop, very tender to frost and light freezes. Plan an average of 2 winter plants per person and two summer plants per 4-6 people. Summer squash can be grown almost anywhere, as the vines develop quickly. Harvest begins in 2 months. Winter squash requires a longer growing season and more garden space for sprawling plants. They generally do not tend to thrive in hot, dry regions where there is a limited water supply.
When to Plant
When the soil is warm and the air temperature settled. Squash are susceptible to frost and cool weather. If the growing season is very short, seed can be started indoors in peat pots for transplanting outdoors 6 weeks later. Use peat pots with the bottom removed; squash do not like to have their taproot disturbed. It is best to transplant before the roots wrap around the pot. For direct sowing wait until the soil temperature is about 60 degrees, or until roses are in bud and lilacs are in bloom.
How to Plant
The hill method is simplest, since the soil can be deeply prepared for each hill before planting. To prepare, dig 18" deep holes, fill partly with well-rotted manure and/or compost; complete filling with a mixture of soil and compost.
Winter squash does not transplant well, but can be sown inside in individual pots to minimize root disturbance. Traditionally 6-8 seeds are placed 1" deep in each hole; when seedlings reach 3 inches, thin to two seedlings.
Summer squash hills should be placed 3 feet apart each way; plant 6 or 7 seeds per hill and thin to the 3 strongest seedlings when the plants are 3 inches high. Or the seeds can be planted sparingly in rows 3 feet apart and thinned to 2 feet apart.
Winter squash hills should be placed 6-8 feet apart each way; thin to the strongest 3 plants when the seedlings are 3 inches high.
How to Grow & Harvest
The squash area should be kept free of weeds while the plants are young. Black-plastic or very heavy mulch is practical for such spreading vine plants, as weeding is difficult. Feed twice, immediately after thinning to the strongest 3 seedlings and again just before the vines start to "run". The plants must have adequate moisture all through the growing season. Note: The popular notation that squash and melon cross-pollinate each other is a fallacy, although they can cross pollinate with other plants such as pumpkin.
Raise fruits off the ground to prevent rot. Use an A frame trellis to grow vines upright. Fabric row covers boost and prolong yields. In cooler climates, keep row covers on all season long; when female (fruit) blossoms open, lift the cover for 2 hours in early morning twice a week to ensure bee pollination, which is essential. To keep vines short for row covers, pinch back the end, choose the best blossoms, and permit only 4 fruits per vine.
Summer - 60-70 days. These squash are picked immature before they are fully formed. The skin should be soft and tender, otherwise the squash will be overripe and of poor quality. Check squash plants almost daily when they start to flower, as the fruit will develop in 2 or 3 days in hot growing weather. The vines must be kept picked or the plants will stop producing.
Winter - 90-120 days. When the stems turn a light green yellow color, the squash should be fully ripe. The rind will be thick and tough. Cut, do not pull, the ripe fruit from the plant. Two to three inches of stem must remain for proper storing. This may increase the sugar content.
Winter squash can also be picked before maturity, and can be eaten whole, just like the summer squash varieties. It has been said that rubbing winter squash with oil will help them last for several months.